Correct paper work for Abandoned/board up homes with tax liens

[Kingsley Obasi]

I am looking to buy a home with cash outright with my investment group in a dilapidated area that I grew up in for 25+ years. I have already compiled a list of properties that are boarded up in the city and began checking the county website for tax liens on the properties. I am using Zillow to show me more information not shown on the county website. I want to start working on obtaining a rental property in the promising sections of the city. I am looking up tax liens on the properties that have boarded up windows and doors. I want to know what paper work should I get to make sure I can acquire the property, pay off the tax liens, and then rebuild the property for a rental unit. I am doing my research but it is a lot to read and some are not very good outcomes like the owner of the property being able to buy the home back after someone acquired a property through the tax lien process some way.